Yokohama Bay Surf Stats

This chart shows the range of swells directed at Yokohama Bay through an average April and is based upon 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the optimum grid node based on what we know about Yokohama Bay. In this particular case the best grid node is 27 km away (17 miles). The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but without direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These happened only 39% of the time. Green and yellow show increasing swell sizes and red illustrates biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell was forecast. The diagram implies that the prevailing swell direction, shown by the largest spokes, was NW, whereas the the prevailing wind blows from the ENE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Yokohama Bay and away from the coast. We lump these in with the no surf category of the bar chart. To keep it simple we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at Yokohama Bay, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical April, swells large enough to cause clean enough to surf waves at Yokohama Bay run for about 61% of the time.

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